This is an employee time clock from about 1900 on display at the Cable Car Museum in San Francisco.

It's description is in the third picture above, but I will transcribe it below.

"This device is rather straight forward, even though it looks intimidating. The main difference to today's time clocks is that, rather than having individual time cards for each employee, all times were recorded together on a roll of paper inside the clock. Each employee had a number, located on one of the buttons on the front of the clock. By moving the arm to the number location and pressing the nose of the arm into the hole next to the number, the print head inside the clock would stamp the time and employee number on the (pay-) roll."